Unless otherwise indicated herein, the materials described in this section are not prior art to the claims and are not admitted to be prior art by inclusion in this section.
When two devices wirelessly communicate with each other over an air interface, the devices may apply an acknowledgement scheme that helps to ensure receipt of transmitted data. According to such a scheme, when one device (transmitting device) transmits a segment of data to another device or is expected to transmit a segment of data to the other device, the other device (receiving device) may determine whether it successfully receives the data and may then responsively send to the transmitting device an acknowledgement message indicating either that it successfully received the data or that it did not successfully receive the data, and if the acknowledgement message indicates lack of successful receipt, the transmitting device may responsively re-transmit the segment of data to the receiving device.
In practice, the acknowledgement message may be either an ACK (positive acknowledgement) to indicate successful receipt or a NACK (negative acknowledgment) to indicate lack of successful receipt, such as non-receipt or receipt with error. When the transmitting device receives such an acknowledgement message from the receiving device, the transmitting device may thus determine whether the acknowledgement message is an ACK or a NACK and may proceed accordingly. In particular, if the transmitting device determines that the acknowledgement message is a NACK, then the transmitting device may responsively re-transmit the segment of data to the receiving device (perhaps adding or substituting some error correction coding to help achieve successful receipt). Whereas, if the transmitting device determines that the acknowledgement message is an ACK, then the transmitting device may responsively not re-transmit the segment of data to the receiving device but may instead proceed to transmit a next segment of data to the receiving device.
Such an acknowledgement scheme can be applied in a cellular wireless communication system, where a base station serves a user equipment device (UE) such as a cell phone or other wirelessly-equipped communication device, and with the scheme applying for data communications in either direction between those entities. For instance, as a UE transmits segments of data over the air to its serving base station, the base station may responsively send acknowledgement messages to the UE to cause the UE to either re-transmit to the base station or to continue with transmission of next data to the base station. Further, as a base station transmits segments of data over the air to a served UE, the UE may responsively send acknowledgement messages to the base station to cause the base station to either re-transmit to the UE or to continue with transmission of next data to the UE.